(a) Field of the Invention
The invention relates to a fan housing assembly and, more particularly, to a fan housing assembly whose different parts are separately formed in view of different quality requirements.
(b) Description of the Related Art
FIG. 1 is a cross-sectional view of a conventional one-piece molding fan housing design. Referring to FIG. 1, the housing 100 includes an outer frame 102, a flange 104, ribs 106 and a bearing tube 108, and all of these parts constituting the one-piece housing 100 are made of the same material by way of injection molding.
However, one-piece injection molding utilized in the formation of the housing 100 suffers from the following disadvantages. First, because the bearing tube 108 located between a bearing and a stator of a motor (not shown) is to position and support the bearing of a fan, the fabrication of the bearing tube 108 requires high precision. Also, because the heat generated from the motor is directly conducted to the bearing tube 108, the material selected for the bearing tube 108 must meet high heat-resistance requirement. However, it is not necessary for other parts of the housing 100 such as the outer frame 102, flange 104 and ribs 106 to meet such high-quality requirements. When the conventional one-piece molding is utilized to fabricate the fan housing, all parts constituting the housing 100 are forced to adopt the same high-quality material so as to meet the quality requirement of the bearing tube 108, thus resulting in a considerable manufacturing cost.
Moreover, the conventional one-piece molding fabrication does not allow the selection of materials for different parts of the housing in view of the specific requirements. For example, it is impossible to fabricate a fan housing whose bearing tube 108 is made of metal to enhance the strength or meet other requirements while other parts are made of plastic, if the conventional one-piece molding fabrication is utilized. Furthermore, when a fan is used in different systems, it is difficult, if the conventional one-piece molding fabrication is utilized, to adapt the design of the fan housing to fit different systems. This significantly reduces the flexibility of a fan housing design.